The prominence of the automobile has caused central city-bound commuting patterns to be increasingly replaced by lateral movements with many suburban residents traveling to suburban work-places. Our proposed research focuses on the nature and implications of contemporary commuting patterns, both lateral (origin and destination within the ring) and centripetal/ centrifugal (ring to central city) in metropolitan areas of the conterminous U.S. Previous research suggests the thesis that these patterns can be best understood within the context of their relationship to population distribution, decentralization of employment, and transportation technology. The objectives of the study are threefold: (1) To identify the nature and extent of lateral as compared to centripetal/centrifugal commuting in U.S. metropolitan areas; (2) To develop a theoretical rationale for observed commuting patterns in terms of metropolitan population and employment distribution, and transportation usage; (3) To examine the implications of lateral commuting patterns and their determinants for future growth and spatial organization of smaller, developing metropolitan areas. The research will be carried out in three phases, using 1970 Census data on metropolitan characteristics and the journey-to-work, as well as data from the 1967 Census of Manufactures. First, lateral commuting rates will be calculated for each U.S. metropolitan area. Then, using these rates as a basis for comparision of areas, an initial analysis will be undertaken by population size, age, Census region, economic function, and proximity to other metropolitan areas. In the second phase, we will attempt to explain the variation in commuting rates with demographic, socioeconomic, and industrial characteristics in a multiple regression analysis. Finally, we will examine the commuting streams in U.S. metropolitan areas in respect to mode of transportation used and the characteristics of commuters.